VESA (Video Electronics Standard Association) developed a new display interface compression standard for mobile or smartphone displays or hand-held devices called VESA Display Compression-Mobile or VDC-M. VDC-M targets higher compression ratio than Display Stream Compression (DSC) while maintaining visually lossless quality as of DSC at the cost of increased complexity. VDC-M has application in mobile devices that use a display link, such as the MIPI display serial interface (DSI). The VDC-M display interface compression standard is described in Jacobson et al., “A new display stream compression standard under development in VESA”, Proc. SPIE 10396, Applications of Digital Image Processing XL, 103960U (19 Sep. 2017).
In particular, the VDC-M compression standard is fixed rate codec (encoder-decoder) and supports compression rates down to 6 bits/pixel for a RGB 4:4:4 signal source with 8 bits per color component. VDC-M is a block based codec with a block size of 8×2 pixels. In operation, the VDC-M codec operates by applying or testing multiple coding modes for each block and selecting a best coding mode for a block based on a rate-distortion cost. A different coding mode may be selected for each block. With the selected coding mode, the data samples are encoded using an entropy encoder to generate a compressed bitstream. Substream multiplexing is implemented to enable parallel parsing of the compressed bitstream to achieve a high decoder throughput.